Construction and maintenance of Reinforced concrete structures near to marine environment are always being challenging to Engineering community keeping durability at a center. The sea salts present in sea water and air, gradually attack concrete and penetrate into body of the concrete structure. The leachable compounds tend to form expansive products and ultimately reduce the mass and compressive strength of the concrete. Delamination further exposes the concrete to chloride attack which in turn increases risk of reinforcement corrosion. The coastal area within few miles of the coast line and off shore structures remain in contact with marine salts present in form of airborne salts or saltwater or both. The physical effects like disintegration, mass loss and expansion etc., if addressed properly, the long term durability issues may be further diluted or may be addressed easily. Mix design, use of supplementary materials and other quality control measure play vital role in preventing physical effects on concrete. The present study examines the physical effects of suphate attack on concrete containing different proportion of fly ash (10, 20, 30%) and GGBS (20, 30, 40%) with M40 and M50 grade of concrete with continuous immersion in sea water conditions and wetting drying cycles. The effects of loss in compressive strength and mass loss is monitored and presented in this paper. The use of GGBS and Fly ash found out to be more effective in continuous immersion conditions compared to wetting drying conditions. Effectiveness and optimum dose of fly ash and GGBS in concrete for experimental conditions are also discussed.